Brake device



April 19 1927.

H. W. `JONKHOFF BRAKE DEVICE Filed Abril 1924 2 Sheets-Sheet 1 L62527 April 19 1927' H. w. JoNKHoFP BRAKE DEVICE 2` S-heets-Sheet 2 Filed April 8. 1924 V/w/ rn/wwe.

'Y Patented Api. 19,1927.

HENRI. 'WOUTER JQNKHOFF, 0F SEANG, JAVA, DTCH naar .miams :Bam DEVICE.

Application led April 8, 1924,

This invention has reference to braking arrangements-@for vehicles which can be automatically put` into operation by the movementof the vehicle in a pre-determined direction, as for example when it commences to run backwards down an incline. In this Y connection, with freight cars and tractor 'back but a few inches. .prevents the vehicle obtaining momentum, when it has again started forward only a few inches the brake- -trains having trailersas 11sedin`mountainous countries there is a need for a wheel brake coming automatically into operation as soon as the vehicle begins to'run back. Almost daily accidents occur which are often caused by the fact that the driver does not act imd mediately, and this, coupled with the time occupied by the take-up of the brakes (adapted to exert a gradually increasing brake-force), is dangerous in critical mo-v .ments On steep inclines,- where the' shortest delay is almost immediately followed by a runmngback, forces at once come into action which cannot be overcome even by the maximum brakeforce.

The invention has for its object to provide means for avoiding the said drawback. According to the invention the existing wheel brakes are combined with an automatically acting device, which is preferablycapable of being rendered operative or inoperative at will. automatic action is derived from the backward wheel` motion of the vehicle in such Va manner that the fullbrake capacity is at once attained as soon as a wheel has run This rapid action and on the other hand action ceases immediately. It is remarked in this instance lthat the invention should not be confused with known devices including pawl-brakes. In a pawl-brake the entire braking resistance'is concentrated upon the running back vehicle,

' v'lbrake-action is also obtained as the pawl shaft or spindle and the recess in vwhich the pawl engages and, such a .con-

struction, especially as 1t comes into operation suddenly, is easily liable to distortion and fracture.

In the construction according to the present invention although use is made of a device comparable to a pawl, this pawl has only a. secondary function and does not necessarily receive the forces developed by as this function is performed by the brake segments of the usual brake in the brake drum. Moreover, according -to the' invention the gradual distinct Serial No. 705,116, and in the Netherlands March 21, 1922.

from. the jarring of a pawl-brake, and the existmg brakes are put on more strongly.

fThereforev with a device according tothe mechanism is not liable tobe brake drum.

Figs. 4 and 5 are side elevations of a vehicle wheel rotating in forward and in 80 rearward directions, respectively.

Fig. 6 shows in side elevation a wheel with the brake device in inoperative posi-V tion.

Fig. 7 shows in side ment with a double acting brake device.

Figs. 1-3 show a brake construction according to the invention.`

Upon the endsuof the vertical axle 1 of the steering swivel 2 a second brake-drum 90 8 is attached adjacent to the usual exist- .mg drum 4 so that the drum 8 is forced to perform all the steering movements of the wlrilelell turning about the same vertical axis.-

e limited degree about its lmaginary horizontal axis by reason of the fact that the vertical axle 1 of the Vsteering swivel 2 projects at both ends through slots 9 formed in the brake-drum and having a length of 10G' about 3 to 4 inches. The partial rotation of the drum 8 is caused on the operation of neans provided to this end as is explained ater.

This second brake drum 8 is connected at 105 the inner side (Figure 1)eat 10 to point 6 of the s ring-lever 5 operation of which, in one irection, results in applying two brake segments against the inner side of the usual brake drum p always be pressed with the slotends 11 against .the .vertical -axle 1f et weiber which device comprises will be more fully under-IV Fig. 3 is a side elevation of the auxiliaryQ elevation an embodisecond brake-drumV 8is rotatable in a 95 4, so that the' drum will HG ed in Figure point 12 at the outer side of this drum a horizontal pivot 13 is arranged about which a bell-crank lever 14 of the shape shown in Figure l is rotatable. l/Vhen 'the wheel moves forwardly opposite to the direction of the arrow 15 the vertical arm 16 of the bell-crank lever will slide along the spokes of the wheel and the said arm will then be pressed down. The longer horizontal arm tends always to move upwards which will occur as soon as the wheel rotates in an o posite directioln, i. e. in ,this case bac wardly. As soon as this occurs the bellcrank lever let will rotate about its horizontal pivot 13 and the other arm 17 will then also enter between the spokes so that the bell-crank lever will perform the function of a pawl and through the pivot 13 will carry the brake-drum '8 in the direction of the backward rotation of the wheel.

As a result the point 10 inside the said drum would be moved away from the point 6 of the sprin 4lever 5 if it were not connected thereto y a cable 19 or another connection. The result therefore will be that the lever 5 is shifted simultaneously with the displacement of the bell-crank lever 14 by the wheel spokes, and the usual brake will at once perform its function with rapidly increasing force, and stops rotation of the wheel before part 1 reaches the end of its slot 9, it being understood that this slot is dimensioned to permit such action.

Now when the vehicle is started forward again Arelease will immediately occur by reason of the lever influence of its spring, so that after a forward motion of but a few inches the brakes will be entirely free. Simultaneously the second brake-drum 8 will return into its original position by the pull exerted on the connection 19. 'Ihe horizontal stud 13 also returns to its original position, while the vertical arm 16 of the bell crank lever 14 will be .pressed down by the opposite rotation of the spokes.

It will be clear that a construction of .this

.kind may be applied to any wheel which is provided in the usualway with a brake. In this embodiment a steerable wheel has been chosen for explaining theapplication of the invention thereto.

Figure 6 shows how the bell-crank lever llt may be locked in an inoperative position by a locking-device at the outer side of the second brake-drum 8 in such a manner that the arms cannot come into contact with the spokes of the wheel. In this position no brake-force can be automaticallyexerted as the member 14 is clear from engagement with the spokes.

The brake-device according to the invention may also7be double acting as illustrat- The connection 10-6 is designed for ten- .will be slackened and vice versa.

5 moving back under the sion. The second brakedrum is now provided diametrically opposite witha second projecting horizontal stud 13 carryin a rotatable bell-crank lever 14. VOne, o these levers or both may be brought and locked into inoperative position. In the brakedrum when a pulling action is exerted on the connection 10-6 the connection 20-6 The slots in the sei-ond drum 8 are in lhis case provided also at the other side of the .vertical axis while the brake-drum is always returned lo ils central position as the two connections with the spring-lever 5 have equal v tension as soon as the action or the brakedevice is finished.

Havingl now particularly Vdescribed and ascertained the nature of my said invention and in what manner the same is to be performed, I declare that what I claim is :s-

1. An automatic device for applying wheel brakes, comprising, mechanism for use with a wheel and its brake, the mechanism including, a drum mounte'd'to remain stationary upon rotation of the Wheel in one direction, detent means to cause the drum to rotate with the wheel upon rotation in the other direction, and connecting means between the drum and the brake arranged to apply the brake upon rotation of the drum, the detent means being a bell crank lever pivoted to the drum, one arm of the lever bearing against the wheel spokes and operating as a pa-wl therewith, whereby in one direction it permits passage of the wheel spokes, and in the other direction it is entrained by the wheel spokes.

2. An automatic device for applying wheel brakes, comprising` mechanism for use with a wheel and its brake, the mechanism includ-` ing, a drum' mounted to remain stationary upon rotation of the wheel in one direction, detent means to cause the drum to rotate with the wheelupon rotation in the other direction, and connecting means between the drum and the brake arranged to apply the brake upon rotation of the drum, the etent means being a. bell crank lever pivoted to thc drum, one arm of the lever bearing against the wheel spokes and operating as a pawl therewith, whereby in one direction it. permits passage of the wheel spokes` and' in the other direction it is entrained h v the 'wheel spokes, the connecting means ineluding a member inlerconnecting'the drum and the operating means for the wheel brake.

3. An automatic device for applying wheel brakes. comprising, mechanism for use with a wheel audits brake, the mechanism in cluding, a drum mounted 'to remain stationary upon rotation of the wheel in one direction, detent 'means to cause the drum in v to rotate with the wheel upon rotation in the deseas? l appl the brake upon rotation of the drum, the drum being mounted for limited rotary motion and positioned adjacent the drum of the wheel brake.

4. An automatic device for applying wheel brakes, comprisin mechanism for use with a wheel and its irake, the mechanism including, a drum mounted to remain station-y ary upon rotation of the wheel in one direction, detent means to cause the drum to rotate with the wheel upon rotation in the other direction, and connecting means between the drum and the brake arranged to apply the brake upon rotation of the drum, the detent means being a bell crank lever Evoted to the drum, one arm of the lever 'aring against the wheel spokes and operating as a pawl therewith, whereby in one direction it permits passage of the wheel spokes' and in the other direction it is entrained by the wheel spokes, the drum being mounted for limited rotary motion'and positioned ad'acent the drum of the wheel brake.

5. A w eel brake applying means for use with a wheel and its rake, comprising, a drum mounted adjacent the drum of the brake, a cable connecting the drum and the operatin lever of the brake and tensioned by rotation of the drum, a two armed pawl device pivoted to the drum and cooperating with the wheel spokes to prevent relative rotation of the drum and the wheel when the wheel rotates in one direction, and to permit relative rotation thereof when the wheel rotates in the other direction, and means limiting rotation of the drum in each direction.

In testimony whereof I aiiix my signature.

HENRI WOUTER JONKHOFF. 

